This study will extend observations made with a roentgenographic technique for measuring tracheal mucous velocity in unanesthetized sheep, normal humans and patients with chronic obstructive lung disease. Investigations will be made of the effects of environmental pollutants, drugs, and cigarette smoking on tracheal mucous velocity. The recovery of tracheal mucous velocity from oxygen suppression will also be determined. An in vivo technique for measuring rheology of mucus will be applied to the study of pathologic conditions. Modification by pharmacologic agents and air pollutants of tracheal mucous velociy will be investigated.